That is the setup I have as well. Factory 15x7, 32x11.50x15. They fit fine under the factory flares. I have been wheelin' with my swaybar off and no rubbing under full flex. (See pix on website below)
They rubbed my leaf springs under full left or right turn, but this was easily corrected by spacing out the steering bump stops with 2 washers on eash side. With that done, I still think my turning radius is better than most other vehicles.
The narrower rim will leave a narrower footprint, but it will also make the tire taller. I don't think either is very noticeable at all. The last thing is with the tire on a rim 1" smaller than recommended, keep an eye on tire pressure as it is a little more critical especially when it comes to tire wear.
Hope this helps
TC